CN114213287A - Process method for improving carbohydrazide yield - Google Patents
Process method for improving carbohydrazide yield Download PDFInfo
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- CN114213287A CN114213287A CN202111642921.4A CN202111642921A CN114213287A CN 114213287 A CN114213287 A CN 114213287A CN 202111642921 A CN202111642921 A CN 202111642921A CN 114213287 A CN114213287 A CN 114213287A
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- 238000000034 method Methods 0.000 title claims abstract description 80
- XEVRDFDBXJMZFG-UHFFFAOYSA-N carbonyl dihydrazine Chemical compound NNC(=O)NN XEVRDFDBXJMZFG-UHFFFAOYSA-N 0.000 title claims abstract description 46
- 238000006243 chemical reaction Methods 0.000 claims abstract description 59
- 239000000047 product Substances 0.000 claims abstract description 45
- 238000002390 rotary evaporation Methods 0.000 claims abstract description 45
- 239000007787 solid Substances 0.000 claims abstract description 36
- 239000012295 chemical reaction liquid Substances 0.000 claims abstract description 35
- WFJRIDQGVSJLLH-UHFFFAOYSA-N methyl n-aminocarbamate Chemical compound COC(=O)NN WFJRIDQGVSJLLH-UHFFFAOYSA-N 0.000 claims abstract description 35
- NWZSZGALRFJKBT-KNIFDHDWSA-N (2s)-2,6-diaminohexanoic acid;(2s)-2-hydroxybutanedioic acid Chemical compound OC(=O)[C@@H](O)CC(O)=O.NCCCC[C@H](N)C(O)=O NWZSZGALRFJKBT-KNIFDHDWSA-N 0.000 claims abstract description 30
- IKDUDTNKRLTJSI-UHFFFAOYSA-N hydrazine monohydrate Substances O.NN IKDUDTNKRLTJSI-UHFFFAOYSA-N 0.000 claims abstract description 30
- 239000000126 substance Substances 0.000 claims abstract description 30
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 claims abstract description 15
- 239000012265 solid product Substances 0.000 claims abstract description 11
- 239000002994 raw material Substances 0.000 claims abstract description 8
- 230000006837 decompression Effects 0.000 claims abstract description 6
- 238000011068 loading method Methods 0.000 claims abstract description 5
- 238000003786 synthesis reaction Methods 0.000 claims description 6
- 238000010025 steaming Methods 0.000 claims description 4
- OWIUPIRUAQMTTK-UHFFFAOYSA-N carbazic acid Chemical compound NNC(O)=O OWIUPIRUAQMTTK-UHFFFAOYSA-N 0.000 claims description 2
- OWIUPIRUAQMTTK-UHFFFAOYSA-M n-aminocarbamate Chemical compound NNC([O-])=O OWIUPIRUAQMTTK-UHFFFAOYSA-M 0.000 claims 1
- GHTQJOFXVXEJPF-UHFFFAOYSA-N COC=O.NN Chemical compound COC=O.NN GHTQJOFXVXEJPF-UHFFFAOYSA-N 0.000 abstract description 5
- 238000000746 purification Methods 0.000 abstract description 3
- 238000009835 boiling Methods 0.000 description 12
- 238000002156 mixing Methods 0.000 description 12
- 230000003247 decreasing effect Effects 0.000 description 8
- 238000001704 evaporation Methods 0.000 description 7
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 6
- 238000004817 gas chromatography Methods 0.000 description 6
- 239000000203 mixture Substances 0.000 description 6
- 238000004448 titration Methods 0.000 description 6
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 4
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 3
- 238000001816 cooling Methods 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000001308 synthesis method Methods 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- HEDRZPFGACZZDS-UHFFFAOYSA-N Chloroform Chemical compound ClC(Cl)Cl HEDRZPFGACZZDS-UHFFFAOYSA-N 0.000 description 2
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 2
- 239000006227 byproduct Substances 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 230000008020 evaporation Effects 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 239000013067 intermediate product Substances 0.000 description 2
- 238000002386 leaching Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 230000035484 reaction time Effects 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- PTYMQUSHTAONGW-UHFFFAOYSA-N carbonic acid;hydrazine Chemical compound NN.OC(O)=O PTYMQUSHTAONGW-UHFFFAOYSA-N 0.000 description 1
- 239000013064 chemical raw material Substances 0.000 description 1
- 239000003431 cross linking reagent Substances 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 239000000975 dye Substances 0.000 description 1
- 210000004177 elastic tissue Anatomy 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 239000004009 herbicide Substances 0.000 description 1
- 150000002429 hydrazines Chemical class 0.000 description 1
- CIEOMWUGKBLMKY-UHFFFAOYSA-N hydrazinylmethyl formate Chemical compound NNCOC=O CIEOMWUGKBLMKY-UHFFFAOYSA-N 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 231100000053 low toxicity Toxicity 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 239000005648 plant growth regulator Substances 0.000 description 1
- 239000003380 propellant Substances 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 238000000967 suction filtration Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C281/00—Derivatives of carbonic acid containing functional groups covered by groups C07C269/00 - C07C279/00 in which at least one nitrogen atom of these functional groups is further bound to another nitrogen atom not being part of a nitro or nitroso group
- C07C281/02—Compounds containing any of the groups, e.g. carbazates
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C281/00—Derivatives of carbonic acid containing functional groups covered by groups C07C269/00 - C07C279/00 in which at least one nitrogen atom of these functional groups is further bound to another nitrogen atom not being part of a nitro or nitroso group
- C07C281/06—Compounds containing any of the groups, e.g. semicarbazides
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The application discloses a process method for improving carbohydrazide yield, which relates to the technical field of chemical purification, and comprises the following steps: the method comprises the following steps: carrying out synthetic reaction by taking dimethyl carbonate and hydrazine hydrate as raw materials to obtain a first reaction liquid; step two: loading the first reaction liquid into a rotary evaporator for decompression rotary evaporation to completely evaporate low-boiling-point substances in the first reaction liquid to obtain a dry solid product of the methyl carbazate; step three: taking hydrazine hydrate and the dry solid hydrazine methyl formate obtained in the second step as raw materials to perform synthetic reaction to obtain a second reaction solution; step four: and (3) putting the second reaction liquid into a rotary evaporator for reduced pressure rotary evaporation to completely evaporate low-boiling-point substances in the second reaction liquid to obtain a carbohydrazide solid dry product. The process method has simple working procedures and high efficiency, and can greatly improve the yield of the carbohydrazide product under the condition of ensuring the purity of the product.
Description
Technical Field
The application relates to the technical field of chemical purification, in particular to a process method for improving the yield of carbohydrazide.
Background
Carbohydrazide (also called Carbohydrazide), which is white short columnar crystal or white crystalline powder at room temperature, is very soluble in water, insoluble in ethanol, and insoluble in alcohol, ether, chloroform and benzene. Carbohydrazide is a derivative of hydrazine, has strong reducibility, can be used as an intermediate for manufacturing energetic materials, and can also be directly used as a component of rocket explosives and propellants. The deoxidant used as boiler water is the most advanced material used as boiler water deoxidization in the world at present, has low toxicity, high melting point and far higher deoxidization efficiency than the used material, and is an ideal product with safety and environmental protection. In addition, carbohydrazide can be used as a cross-linking agent of elastic fibers in the chemical fiber industry, as a chemical raw material and a chemical intermediate, and can be widely used in the industries of medicines, herbicides, plant growth regulators, dyes and the like.
The common synthesis method of carbohydrazide is a carbonate hydrazine hydrolysis method, one of which is to firstly use dimethyl carbonate and hydrazine hydrate to react to generate methyl carbazate, and then use methyl carbazate and hydrazine hydrate to react to generate carbohydrazide. The reaction equation is as follows:
the refining and purifying method usually adopted by the synthesis method comprises the steps of cooling and crystallizing reaction liquid, filtering, and finally drying to obtain the product. The specific process comprises the following steps:
step 1: adding dimethyl carbonate and hydrazine hydrate in a certain ratio into a three-neck flask, stirring, heating to a certain temperature for reaction, cooling reaction liquid to 0 ℃ for crystallization after the reaction is finished, performing suction filtration, methanol leaching and drying to finally obtain white crystalline powder, namely, methyl carbazate, wherein the yield is about 97%;
step 2: adding hydrazine hydrate and methyl carbazate in a certain ratio into a three-neck flask, stirring, heating to a certain temperature for reaction, cooling the reaction liquid to 0 ℃ after the reaction is finished, crystallizing, filtering, leaching with methanol, and drying to obtain a white crystal, namely carbohydrazide with the yield of about 80%.
The purification process has the advantages of complex working procedures and multiple steps, and the yield of the carbohydrazide is low and is only about 80%.
Disclosure of Invention
Therefore, the application provides a process method for improving the yield of carbohydrazide, and aims to solve the problems of complex process, low product yield and the like of the carbohydrazide synthesis method.
In order to achieve the above purpose, the present application provides the following technical solutions:
according to a first aspect of the present application, a process for increasing carbohydrazide yield, the process comprising the steps of:
the method comprises the following steps: carrying out synthetic reaction by taking dimethyl carbonate and hydrazine hydrate as raw materials to obtain a first reaction liquid;
step two: loading the first reaction liquid into a rotary evaporator for decompression rotary evaporation to completely evaporate low-boiling-point substances in the first reaction liquid to obtain a dry solid product of methyl carbazate;
step three: taking hydrazine hydrate and the dry solid hydrazinoformate obtained in the second step as raw materials to perform a synthesis reaction to obtain a second reaction solution;
step four: and (3) loading the second reaction liquid into a rotary evaporator, and carrying out reduced pressure rotary evaporation to completely evaporate low-boiling-point substances in the second reaction liquid to obtain a carbohydrazide solid dry product.
According to the process method for improving the yield of the carbohydrazide, methyl carbazate is generated by reacting dimethyl carbonate with hydrazine hydrate, then the methyl carbazate is generated by reacting the methyl carbazate with the hydrazine hydrate, the reaction liquid obtained in the reaction process is directly subjected to reduced pressure rotary evaporation, and a product is crystallized and separated out along with gradual evaporation of low-boiling-point substances and can be dried, so that a solid dry product is directly obtained. The process method has simple working procedures and high efficiency, and can greatly improve the yield of the product under the condition of ensuring the purity of the product.
Further, in the first step, the molar ratio of the dimethyl carbonate to the hydrazine hydrate is 1:0.9-1.1, the temperature of the synthesis reaction is 40-70 ℃, and the time is 0.5 h.
The method has the advantages that the ratio of the reaction raw materials, the reaction temperature and the reaction time in the step I are controlled, so that the synthetic reaction of the intermediate product of the methyl carbazate is more sufficient, the generation of byproducts is reduced, and the reaction yield is improved.
Further, in the second step, the time of the reduced pressure rotary evaporation is 2-5 h.
The yield of the dry solid hydrazinomethyl formate product can be improved by controlling the reduced pressure rotary evaporation time in the second step.
Further, in the second step, in the reduced pressure rotary evaporation process, the temperature is gradually increased from 45-55 ℃ to 60-70 ℃.
This application is through the control to decompression rotary evaporation temperature in the step two, makes the temperature rise gradually, can evaporate out several kinds of substances that are lower than methyl carbazate boiling point in the reaction solution in proper order, and be unlikely to evaporate out methyl carbazate for methyl carbazate almost zero loss, thereby can improve the yield of methyl carbazate solid dry product.
Further, in the second step, in the process of reduced pressure rotary evaporation, the vacuum degree is gradually reduced from-0.070 to-0.080 Mpa to-0.09 to-0.099 Mpa.
The application enables the vacuum degree to be gradually reduced by controlling the reduced pressure rotary evaporation vacuum degree in the step two, and can reduce the boiling point of low boiling point substances in the reaction liquid, so that the low boiling point substances can reach the boiling point at a lower temperature and are evaporated out, and the hydrazine methyl formate is not steamed out, so that almost zero loss of the hydrazine methyl formate is caused, and the yield of solid dry products of the hydrazine methyl formate can be improved.
Further, in the third step, the molar ratio of the hydrazine hydrate to the dry solid hydrazine methyl formate is 1.5-3:1, the temperature of the synthesis reaction is 75-85 ℃, and the time is 2 hours.
The method controls the ratio of the reaction raw materials, the reaction temperature and the reaction time in the third step, so that the synthetic reaction of the final product carbohydrazide is more sufficient, the generation of byproducts is reduced, and the reaction yield is improved.
Furthermore, in the fourth step, the decompression rotary steaming time is 3-6 h.
Further, in the fourth step, in the reduced pressure rotary steaming process, the temperature is gradually increased from 55 ℃ to 65 ℃ to 85 ℃ to 95 ℃.
The application gradually raises the temperature by controlling the reduced pressure rotary evaporation temperature in the fourth step, and can evaporate several substances with lower boiling points than carbohydrazide in the reaction liquid in sequence without evaporating the carbohydrazide out, so that the carbohydrazide is almost zero in loss, and the yield of the solid dry carbohydrazide product can be improved.
Furthermore, in the fourth step, in the process of reduced pressure rotary evaporation, the vacuum degree is gradually reduced from-0.075 to 0.085Mpa to-0.09 to 0.099 Mpa.
The vacuum degree is gradually reduced by controlling the decompression rotary evaporation vacuum degree in the fourth step, the boiling point of low boiling point substances in the reaction liquid can be reduced, the low boiling point substances can reach the boiling point at a lower temperature and are evaporated, carbohydrazide cannot be evaporated out, the carbohydrazide is almost zero loss, and the yield of dry carbohydrazide solid products can be improved.
This application has following advantage:
according to the process method for improving the yield of the carbohydrazide, methyl carbazate is generated by reacting dimethyl carbonate with hydrazine hydrate, then the methyl carbazate is generated by reacting the methyl carbazate with the hydrazine hydrate, the reaction liquid obtained in the reaction process is directly subjected to reduced pressure rotary evaporation, and a product is crystallized and separated out along with gradual evaporation of low-boiling-point substances and can be dried, so that a solid dry product is directly obtained. The process method has simple working procedures and high efficiency, and can greatly improve the yield of the product (the yield of the methyl carbazate is more than or equal to 99 percent and the yield of the carbohydrazide is more than or equal to 98 percent) under the condition of ensuring the purity of the product (the purity of the methyl carbazate is more than or equal to 99 percent and the purity of the carbohydrazide is more than or equal to 98 percent).
Detailed Description
The present disclosure is not intended to be limited to the particular embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
Example 1
The method comprises the following steps: mixing 99.9% of dimethyl carbonate and 80% of hydrazine hydrate according to a molar ratio of 1: the first reaction solution is obtained by carrying out synthetic reaction for 0.5h at the temperature of 50 ℃ according to the mixture ratio of 0.9.
Step two: adding the obtained first reaction solution into a single-neck flask, putting into a rotary evaporator for reduced pressure rotary evaporation, starting from 50 ℃ in the rotary evaporation process, starting from-0.075 Mpa in vacuum degree, then slowly increasing the temperature and decreasing the vacuum degree, finally increasing the temperature to 65 ℃, and decreasing the vacuum degree to-0.095 Mpa, wherein the control time of the whole process is 4 h. And (3) completely distilling out low-boiling-point substances in the first reaction liquid to obtain a dry solid product of the methyl carbazate. The purity of the solid dry product of the methyl carbazinate determined by the gas chromatography is 99.5 percent, and the yield is 99.6 percent.
Step three: and (3) mixing the solid dry product of the methyl carbazate obtained in the step (II) with 80% hydrazine hydrate according to a molar ratio of 1: 2.5, carrying out synthetic reaction at the temperature of 85 ℃ for 2h to obtain a second reaction solution;
step four: adding the obtained second reaction solution into a single-neck flask, putting the single-neck flask into a rotary evaporator to perform reduced pressure rotary evaporation, starting the temperature from 60 ℃ and the vacuum degree from-0.08 MPa during the rotary evaporation, then slowly increasing the temperature and reducing the vacuum degree, finally increasing the temperature to 90 ℃, and reducing the vacuum degree to-0.095 MPa, wherein the control time of the whole process is 5 hours. And (3) completely evaporating low-boiling-point substances in the second reaction liquid to obtain a carbohydrazide solid dry product. The purity of carbohydrazide solid dry product determined by titration method is 98.8%, and the yield is 98.7%.
Example 2
The method comprises the following steps: mixing 99.9% of dimethyl carbonate and 80% of hydrazine hydrate according to a molar ratio of 1: the mixture ratio of 0.9 is subjected to synthetic reaction at the temperature of 50 ℃ for 0.5h to obtain a first reaction solution;
step two: adding the obtained first reaction solution into a single-neck flask, putting into a rotary evaporator for reduced pressure rotary evaporation, starting from 45 ℃ and vacuum degree of-0.07 Mpa during rotary evaporation, then slowly increasing the temperature and reducing the vacuum degree, finally increasing the temperature to 60 ℃ and reducing the vacuum degree to-0.09 Mpa, and controlling the time of the whole process to be 5 h. And (3) completely distilling out low-boiling-point substances in the first reaction liquid to obtain a dry solid product of the methyl carbazate. The purity of the solid dry product of the methyl carbazinate determined by the gas chromatography is 99.3 percent, and the yield is 99.2 percent.
Step three: and (3) mixing the solid dry product of the methyl carbazate obtained in the step (II) with 80% hydrazine hydrate according to a molar ratio of 1: 2.5, carrying out synthetic reaction for 2h at the temperature of 85 ℃ to obtain a second reaction solution.
Step four: adding the obtained second reaction solution into a single-neck flask, putting into a rotary evaporator for reduced pressure rotary evaporation, starting from 55 ℃ in the rotary evaporation process, starting from-0.075 Mpa in vacuum degree, then slowly increasing the temperature and the vacuum degree, finally increasing the temperature to 85 ℃, and finally reducing the vacuum degree to-0.09 Mpa, wherein the control time of the whole process is 6 h. After low boiling point substances in the reaction liquid are completely evaporated, a carbohydrazide solid dry product is obtained, the purity is 98.6 percent and the yield is 98.8 percent through a titration method.
Example 3
The method comprises the following steps: mixing 99.9% of dimethyl carbonate and 80% of hydrazine hydrate according to a molar ratio of 1: the first reaction solution is obtained by carrying out synthetic reaction for 0.5h at the temperature of 50 ℃ according to the mixture ratio of 0.9.
Step two: adding the obtained first reaction solution into a single-neck flask, putting into a rotary evaporator for reduced pressure rotary evaporation, starting from 55 ℃ and vacuum degree of-0.08 MPa during rotary evaporation, then slowly increasing the temperature and reducing the vacuum degree, finally increasing the temperature to 70 ℃, and reducing the vacuum degree to-0.099 MPa, wherein the control time of the whole process is 2 h. And (3) completely distilling out low-boiling-point substances in the first reaction liquid to obtain a dry solid product of the methyl carbazate, wherein the purity of the dry solid product of the methyl carbazate is 99.6% and the yield is 99.8% by gas chromatography.
Step three: and (3) mixing the solid dry product of the methyl carbazate obtained in the step (II) with 80% hydrazine hydrate according to a molar ratio of 1: 2.5, carrying out synthetic reaction for 2h at the temperature of 85 ℃ to obtain a second reaction solution.
Step four: adding the obtained second reaction solution into a single-neck flask, putting into a rotary evaporator, performing reduced pressure rotary evaporation at the temperature of 65 ℃ and the vacuum degree of-0.085 Mpa, slowly increasing the temperature and reducing the vacuum degree, finally increasing the temperature to 95 ℃, and reducing the vacuum degree to-0.099 Mpa, wherein the control time of the whole process is 3 h. After low boiling point substances in the second reaction liquid are completely evaporated, a carbohydrazide solid dry product is obtained, and the purity of the carbohydrazide solid dry product is determined by a titration method to be 98.7%, and the yield is 98.5%.
Comparative example 1
The method comprises the following steps: mixing 99.9% of dimethyl carbonate and 80% of hydrazine hydrate according to a molar ratio of 1: the first reaction solution is obtained by carrying out synthetic reaction for 0.5h at the temperature of 50 ℃ according to the mixture ratio of 0.9.
Step two: adding the obtained first reaction solution into a single-neck flask, putting into a rotary evaporator for reduced pressure rotary evaporation, starting from 45 ℃ in the rotary evaporation process, starting from-0.075 Mpa in vacuum degree, then slowly increasing the temperature and decreasing the vacuum degree, finally increasing the temperature to 55 ℃, and decreasing the vacuum degree to-0.095 Mpa, wherein the control time of the whole process is 5 h. And (3) completely distilling out low-boiling-point substances in the first reaction liquid to obtain a dry solid product of the methyl carbazate. The purity of the solid dry product of methyl carbazinate determined by gas chromatography was 97.3%, and the yield was 97.2%.
Step three: and (3) mixing the solid dry product of the methyl carbazate obtained in the step (II) with 80% hydrazine hydrate according to a molar ratio of 1: 2.5, carrying out synthetic reaction at the temperature of 85 ℃ for 2h to obtain a second reaction solution;
step four: adding the obtained second reaction solution into a single-neck flask, putting the single-neck flask into a rotary evaporator to perform reduced pressure rotary evaporation, starting the temperature from 60 ℃ and the vacuum degree from-0.08 Mpa during the rotary evaporation, then slowly increasing the temperature and reducing the vacuum degree, finally increasing the temperature to 80 ℃, and reducing the vacuum degree to-0.095 Mpa, wherein the control time of the whole process is 6 hours. And (3) completely evaporating low-boiling-point substances in the second reaction liquid to obtain a carbohydrazide solid dry product. The purity of the carbohydrazide solid dry product determined by a titration method is 96.4%, and the yield is 95.1%.
Comparative example 2
The method comprises the following steps: mixing 99.9% of dimethyl carbonate and 80% of hydrazine hydrate according to a molar ratio of 1: the first reaction solution is obtained by carrying out synthetic reaction for 0.5h at the temperature of 50 ℃ according to the mixture ratio of 0.9.
Step two: adding the obtained first reaction solution into a single-neck flask, putting into a rotary evaporator for reduced pressure rotary evaporation, starting from 50 ℃ in the rotary evaporation process, starting from-0.075 Mpa in vacuum degree, then slowly increasing the temperature and decreasing the vacuum degree, finally increasing the temperature to 65 ℃, and decreasing the vacuum degree to-0.085 Mpa, wherein the control time of the whole process is 5 hours. And (3) completely distilling out low-boiling-point substances in the first reaction liquid to obtain a dry solid product of the methyl carbazate. The purity of the solid dry product of methyl carbazinate determined by gas chromatography was 96.9%, and the yield was 97.5%.
Step three: and (3) mixing the solid dry product of the methyl carbazate obtained in the step (II) with 80% hydrazine hydrate according to a molar ratio of 1: 2.5, carrying out synthetic reaction at the temperature of 85 ℃ for 2h to obtain a second reaction solution;
step four: adding the obtained second reaction solution into a single-neck flask, putting the single-neck flask into a rotary evaporator to perform reduced pressure rotary evaporation, starting the temperature from 60 ℃ and the vacuum degree from-0.08 MPa during the rotary evaporation, then slowly increasing the temperature and reducing the vacuum degree, finally increasing the temperature to 90 ℃, and reducing the vacuum degree to-0.085 MPa, wherein the control time of the whole process is 6 hours. And (3) completely evaporating low-boiling-point substances in the second reaction liquid to obtain a carbohydrazide solid dry product. The purity of the carbohydrazide solid dry product determined by a titration method is 96.2 percent, and the yield is 94.8 percent.
Comparative example 3
The method comprises the following steps: mixing 99.9% of dimethyl carbonate and 80% of hydrazine hydrate according to a molar ratio of 1: the first reaction solution is obtained by carrying out synthetic reaction for 0.5h at the temperature of 50 ℃ according to the mixture ratio of 0.9.
Step two: adding the obtained first reaction solution into a single-neck flask, putting into a rotary evaporator for reduced pressure rotary evaporation, starting from 50 ℃ in the rotary evaporation process, starting from-0.075 Mpa in vacuum degree, then slowly increasing the temperature and decreasing the vacuum degree, finally increasing the temperature to 65 ℃, and decreasing the vacuum degree to-0.095 Mpa, wherein the control time of the whole process is 1 h. And (3) completely distilling out low-boiling-point substances in the first reaction liquid to obtain a dry solid product of the methyl carbazate. The purity of the solid dry product of methyl carbazinate determined by gas chromatography was 96.7%, and the yield was 97.1%.
Step three: and (3) mixing the solid dry product of the methyl carbazate obtained in the step (II) with 80% hydrazine hydrate according to a molar ratio of 1: 2.5, carrying out synthetic reaction at the temperature of 85 ℃ for 2h to obtain a second reaction solution;
step four: adding the obtained second reaction solution into a single-neck flask, putting the single-neck flask into a rotary evaporator to perform reduced pressure rotary evaporation, starting the temperature from 60 ℃ and the vacuum degree from-0.08 MPa during the rotary evaporation, then slowly increasing the temperature and reducing the vacuum degree, finally increasing the temperature to 90 ℃, and reducing the vacuum degree to-0.095 MPa, wherein the control time of the whole process is 2 hours. And (3) completely evaporating low-boiling-point substances in the second reaction liquid to obtain a carbohydrazide solid dry product. The purity of the carbohydrazide solid dry product determined by a titration method is 96.3 percent, and the yield is 94.6 percent.
From the experimental results of the above examples and comparative examples, it can be seen that the process for improving the yield of carbohydrazide can more effectively improve the purity and yield of intermediate products and final products by selectively controlling the time, temperature and vacuum degree in the reduced pressure rotary evaporation process. The process method has the advantages of simple process and high efficiency, and can greatly improve the yield of the product (the yield of the methyl carbazate is more than or equal to 99 percent, and the yield of the carbohydrazide is more than or equal to 98 percent) under the condition of ensuring the purity of the product (the purity of the methyl carbazate is more than or equal to 99 percent and the purity of the carbohydrazide is more than or equal to 98 percent).
Although the present application has been described in detail with respect to the general description and the specific examples, it will be apparent to those skilled in the art that certain changes and modifications may be made based on the present application. Accordingly, such modifications and improvements are intended to be within the scope of this invention as claimed.
Claims (9)
1. The process method for improving the yield of carbohydrazide is characterized by comprising the following steps of:
the method comprises the following steps: carrying out synthetic reaction by taking dimethyl carbonate and hydrazine hydrate as raw materials to obtain a first reaction liquid;
step two: loading the first reaction liquid into a rotary evaporator for decompression rotary evaporation to completely evaporate low-boiling-point substances in the first reaction liquid to obtain a dry solid product of methyl carbazate;
step three: taking hydrazine hydrate and the dry solid hydrazinoformate obtained in the second step as raw materials to perform a synthesis reaction to obtain a second reaction solution;
step four: and (3) loading the second reaction liquid into a rotary evaporator, and carrying out reduced pressure rotary evaporation to completely evaporate low-boiling-point substances in the second reaction liquid to obtain a carbohydrazide solid dry product.
2. The process of claim 1, wherein in the first step, the molar ratio of the dimethyl carbonate to the hydrazine hydrate is 1:0.9-1.1, the temperature of the synthesis reaction is 40-70 ℃, and the time is 0.5 h.
3. The process of claim 1, wherein in step two, the time for reduced pressure rotary evaporation is 2-5 h.
4. The process according to claim 3, wherein in the second step, the temperature is gradually increased from 45 ℃ to 55 ℃ to 60 ℃ to 70 ℃ during the reduced pressure rotary evaporation.
5. The process method as claimed in claim 3, wherein in the second step, the vacuum degree is gradually reduced from-0.070 to-0.080 MPa to-0.09 to-0.099 MPa in the reduced pressure rotary steaming process.
6. The process of claim 1, wherein in step three, the molar ratio of the hydrazine hydrate to the solid dry carbazate is 1.5-3:1, the temperature of the synthesis reaction is 75-85 ℃, and the time is 2 h.
7. The process of claim 1, wherein in step four, the reduced pressure rotary evaporation time is 3 to 6 hours.
8. The process according to claim 7, wherein in the fourth step, the temperature is gradually increased from 55 ℃ to 65 ℃ to 85 ℃ to 95 ℃ during the reduced pressure rotary evaporation.
9. The process according to claim 7, wherein in the fourth step, the vacuum degree is gradually reduced from-0.075 to-0.085 MPa to-0.09 to-0.099 MPa in the reduced pressure rotary steaming process.
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|---|---|---|---|---|
| US4496761A (en) * | 1982-08-17 | 1985-01-29 | Olin Corporation | Process for making carbohydrazide |
| CN109574870A (en) * | 2018-12-25 | 2019-04-05 | 维思普新材料（苏州）有限公司 | A kind of continuous preparation method of hydrazides |
| CN114031524A (en) * | 2021-11-10 | 2022-02-11 | 胜华新能源科技(东营)有限公司 | Method for synthesizing carbohydrazide |
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| US4496761A (en) * | 1982-08-17 | 1985-01-29 | Olin Corporation | Process for making carbohydrazide |
| CN109574870A (en) * | 2018-12-25 | 2019-04-05 | 维思普新材料（苏州）有限公司 | A kind of continuous preparation method of hydrazides |
| CN114031524A (en) * | 2021-11-10 | 2022-02-11 | 胜华新能源科技(东营)有限公司 | Method for synthesizing carbohydrazide |
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